Case-mix classification for emergency departments.

This study developed a patient classification system for hospital emergency departments. Conducted at three Los Angeles area community hospitals, data collection included coding and abstracting medical records information, patient billing information detailing each patient's utilization of hospital services, and patient-specific provider time measuring each provider's time spent in direct patient care activities. A 20,000 patient sample was derived containing clinical and resource use variables, including physician, emergency department, and ancillary service direct costs. Patient visits were classified into 216 homogeneous groups, or patient clusters, using four types of variables: diagnoses, disposition, age, and physician procedures. The Emergency Department Groups (EDGs) appear to represent a clinically coherent system for classifying emergency department visits; moreover, the groups were found to explain 63% of the overall variance in resource use (total direct cost) suggesting that the EDGs may offer a useful tool for hospital cost control and reimbursement reform.